Means for controlling the supply of mixture to internal-combustion engines



' V G. KEITH ETAL.

F-OR CONTR OLLING THE SUPPLY OF MIXTURE TO INTERNAL COMBUSTION ENGINES Filed May 13'', l 922 Patented i i/Kay 2 9,

warren stares learner caries.

GEORGE KEITH AND WILFRED AMBROSE WHATMOUGH, OF LONDON, ENGLAND.

MEANS FOR CONTROLLING THE SUPPLY OF MIXTURE T INTERNAL-COMBUSTION ENGINES.

Application filed May 13, 1922. Serial No. 560,851.

To all whom it may concern:

Be it known that we, GEORGE KEITH and vVrLrRnn AMBRosE VVHATMOUGH, subj ects of the King of the United Kingdom of Great Britain and Ireland, and residing at London, England, have invented a certain new and useful Improvement in Means for Controlling the Supply of Mixture to Internal- Combustion Engines, of which the follow- 1N ing is a specification.

This invention relates to means for controlling the supply of mixture to internal combustion engines, and comprises certain improvements on the apparatus described in the specification of Letters Patent No.

1317709 in which vaporized fuel is supplied to the throat of a Venturi tube through a valve governed by the difference in pressure between two points in the venturi.

The apparatus described in the said specification included provision for loading the piston of the governor as the governor valve shut oii to allow for the circumstance that as the throttle valve is closed a higher vacuum is set up in the induction pipe, with the result that there is a tendency for air to enter at the valve stems and any other points of leakage.

In effect, provision was made to avoid such dilution of the mixture as to prevent firing.

It has been found in practice that there is a further reason for requiring to compensate the mixture, as it is possible to run an engine with a weak economical mixture which will fire satisfactorily under high compression, but will not fire when the engine isrunning light.

The use of a spring or similar device for 40 loading the piston was not entirely satisfactory, as the adjustment of the spring was quite empirical.

We have now devised compensating means which efiect a progressive increase of richness of the mixture as the vacuum in the induction pipe rises, the rate of increase being adjustable while the engine is running to meet exactly the necessities of the case, the progression being correct under all conditions of power and speed.

The invention comprises compensating means suitable for use where the admixture of fuel and air is effected between the throttle valve andthe engine, and means suitable for use where the throttle valve is arranged between the point of admixture of fuel and air and the engine.

The first case is illustrated diagrammatically in vertical section in Fig. 1; the second case is similarly illustrated in Fig. 2 of the accompanying drawings.

l/Ve shall first describe the arrangement shown in Fig. l in which the admixture of air with fuel that passes the obturator at C is effected between the throttle valve A and the engine, and which, like the apparatus described in the said specification, includes a piston D arranged to operate a hollow valve 'E. It will be understood that the valve E,

through its graduated ports Z, controls the admission of fuel vapor from the pipe W to the induction pipe B and the engine. port X is arranged to transmit the pressure which exists at the wider part of the Venturi tube B to the back ofthe piston D. At some point at the back of the piston D (say. in the cover of the cylinder Y) thereis a small opening leading from the outside air through a pipe I and controllable by a pet cock or the like at F. If this opening be closed entirely, the mixture in the induction pipe will remain constant throughout all conditions. If the cock at F be opened, the mixture in the induction pipe will become progressivelyricher as the throttle valve A is closed; or, rather, as the vacuum increases in the induction pipe. The greater the extent. of opening of the pet cock at F, the greater will the increase of richness become as the vacuum in the induction pipe or Venturi tube B increases. As the throttle valve A is opened and the vacuum falls, the effect of the opening of the pet cock at F will diminish till it practically disappears altogether when the engine is running with the throttle valve full open.

This action is accounted for by reason that if the pet cock at F be entirely closed the static pressure at the back of the piston D will be the same as exists at the end of the port X in the Venturi tube B; but if the pet cock at F be slightly open there must be a flow of air along the port X from the back of the piston D into the Venturi tube B, the rate of such flow being greater the greater the vacuum in the induction pipe and therefore in the Venturi tube B. As such flow along the port X cannot take place without a difi'erence'of pressure, it follows that the pressure existing at the back of the piston D must be greater than the pressure existing at the Venturi tube end of the port X, so that the higher the vacuum in the induction pipe the greater. will be the difference be- I tween the pressure at the Venturi tube end ness of the mixture.

of the port X and'the pressure on the backof the piston D. a

By variation of the opening of the pet cock at F exact compensation may be ob tained throughout all conditions of, pressure intheinductionpipe' As the pressure existing in the induction pipe determines both the amount of air leakage and also the final compression of the mixture, the compensat ing device ensures the correct degree ofrich- In the second case 2) here the admixture of gas and, air is effected in the Venturi'tube H or choke bore at a point more remote from the engine than the throtitle valve (is small pipe M connects the gas or vapor side of the piston K and the engine side of the throttle valve G, an adjusting valve at N being arranged at some point invthe said pipe M. The piston K is connected with and operates a valve L controlling, through its graduated ports Z, the passageof vapor fuel to the induction pipe H and the engine. When the adjusting valve at N is entirely closed, the mixture in the induction pipe willbe constant throughout all throttle valve A increases.

conditions. Ifthe adjusting valve at N be opened, the mixture in the induction pipe Will become progressively richer as the vacuum in the lnductlon pipe beyond the The arrangement shown in F i312 operates by'a; direct addition of gasor vapor through the connecting pipe to the mixture which, has been already provided by flow of gasor vapor past. the obturator at J into the Venturi tubeH infront of the throttle valve G.

As the throttle valve G is opened and the V vacuum decreases in the industion pipe, the

amount of enriching gas or vapor pulled.

is movable, a 7

system With the end of said cylinderlremote,

vacuum in the induction pipe:

' l/Vhat We claim is r 1. For. controlling the supply of mixture to internal combustionengines, the combination with the induct on pipe leading to the englne, of a governor devlce comprising a valve in the path of the fuel'component flowingto the induction pipe, a piston determining by its position the extent of opening of said valve, .a cylinder in Which'said piston is'inova-ble, a valve controlling the admission of fuel to said induction pipe; a

fluid conduit communicatingwith the cha nber of said cylinder, and means'for'controlling the passage of fluid through said, 1'

:conduit; whereby a progressiveincrease-in the richness of the mixture as the vacuum in the induction pipe increases may be effected the engine is running.

2. For controlling the supply oflmixture to internal combustion engines, the'combt the rate of increase being adjustable While? v nation with the induction pipe, of a gov-I ernor device comprising a valve in the path of the fuel component flowing to the induc tion pipe and a piston operatively connected tosaid valve, a cylinderinwhich said piston port connecting the. induction from the engine, a pipe connectedftoisaid f cylinder, and valve means fitted to said pipe n testimony whereof We have signed "our names to this specification in the presence if tWo subscribing Witnesses.

stores KEITH.

WILFRED AMBROSE WHATMQUGHL Witnesses: I V v ISABEL RoLLo, 

